The use of dispensers to dispense a solid product by use of water or diluents are known in the art. Such dispensers may be used for many purposes, one of which is to provide active bleach for washing operations. Active bleach is a common component of many washing or sanitizing processes including, washing of kitchenware, tableware, flatware, cookware, etc., laundry, healthcare appliances, food manufacturing equipment, pharmaceutical manufacturing equipment, etc.
A variety of active bleaching compositions are known including oxidant compounds such as halogen and peroxy bleaches. Active halogen compositions have been used for many years in a variety of cleaning or sanitizing methods. Such halogen sources can come in the form of gases (gaseous Cl.sub.2, Br.sub.2. etc.), liquids (aqueous sodium hypochloride), or solids, calcium hypochloride, chlorinated sodium tripolyphosphate, chlorinated isocyanuric acid and others. Solids can be dissolved in water to create a bleach concentrate.
Solid sources of halogen bleaches have been used in both aqueous solutions, particulate powders or in solid tablet or brick form. The solid tablet or brick form of the solid active bleach source can be used in aqueous dispensers. The dispensers can be calibrated to provide various bleach concentrations, often to provide 1 to 28 grams of halogen or 8 to 125 gm of a peroxy bleach, per bleach cycle.
Generally, the solid tablet or brick is loaded into an aqueous dispenser and advanced within a tablet reservoir to sit directly on a reservoir screen at a predetermined distance from an aqueous spray. As the aqueous spray contacts the surface of solid bleach material the water dissolves a portion of the bleach source creating a liquid bleach concentrate which is directed to a wash bleach cycle. The fixed distance between the spray nozzle and tablet is important in regulating the concentration of bleach released from the tablet.
Solid tablets or bricks of bleach can, however, pose a problem in dispensing. For example, the water spray used to dissolve the bleach tablet can be absorbed by the tablet and can soak through the entire tablet or brick causing the tablet to swell. Such water-soaked tablets can be difficult to dispense due to swelling which causes the sides of the tablet to expand against the walls of the reservoir. As the water erodes the bottom surface of the tablet, the tablet will not advance within the reservoir. Hence, the constant distance between the aqueous spray nozzle and product is lost which can cause significant variation in the concentration of the bleach liquor entering the washing site.
Some solid bleach sources also tend to flake or dust. Contact with the odor or dust of the solid bleach tablets can be annoying or even irritating to some individuals.
The encapsulation of active sources of halogen bleach with organic and inorganic coatings have been disclosed in, for example, Choy et al., U.S. Pat. No. 4,741,858; Olson, U.S. Pat. No. 4,279,764; Brubaker, U.S. Pat. No. 4,279,764; Brennen, U.S. Pat. No. 3,637,509; Idudson, U.S. Pat. No. 3,650,961; Alterman, U.S. Pat. Nos. 3,983,254 and 3,908,045. However, coating of a bleach tablet to facilitate advancement of the tablet in a dispenser apparatus or to reduce odor or dust has not been disclosed.
Accordingly, there exists a need for processes using solid bleach sources to provide a solid bleach source that can dispense a uniform proportion of the solid mass of the source without effecting the distance between the spray nozzle and product. There also exists a need to reduce the odor and dusting of solid bleach tablets.